simple question: open another m file

sorry to ask. if I sub 2 variables(x,y) from the currently running first.m into second.m, and second.m will return 2 variables (a,b) back to first.m. I should write this in first.m:

[a,b]=second(x,y);

PS.the location of first.m and second.m is the same.

error message is: ??? Attempt to execute SCRIPT second as a function: C:\second.m

Answer 1

[Walter Roberson]

You can only use that syntax if the first line of the file second.m (that is not whitespace or all comments) starts with the keyword "function", such as

function [p,q] = second(m,n)

If second.m does not start with "function" then it is called a "script". Scripts cannot be passed parameters and cannot return values. Scripts do not have dummy parameter names like functions do. On the other hand, scripts have access to all of the variables of the function that starts them, and can read and write to those variables directly.

[Hello Blower]

if i don't need return values, can i write like:

second(x,y);

thank you

[Walter Roberson]

You can do that if and only if "second" is defined as a function. If "second" is a script instead of a function, you cannot have anything after it (except comments) until the end of the statement.

[Hello Blower]

how to define it is function or script?

[Hello Blower]

I have sent you mentioned program. can you help me to check what cause the problem?

Thanks a lot.

[Hello Blower]

Sorted. I found I have to add "function [a,b] = second(x,y)" at the first line of second.m to make it as a function.